After becoming confident with the beginner's method, "fingertricks" can be used to decrease time universally and across all methods. Fingertricking is moving a layer of the cube without using one's entire hand / wrist. The easiest and most intuitive fingertrick is performing a U turn with one's right index finger.
U: Right index finger. U': Left index finger.
R: Thumb and middle fingers. R': Thumb and middle fingers.
L: Thumb and middle fingers. L': Thumb and middle fingers.
F: Right index finger. F': Right thumb.
D: Ring finger. D': Ring finger.
B: Ring finger / index finger. B': Ring finger / index finger.
M: Ring finger on DB, push up. M': Ring finger on DB, push forward.
180 degree turns can be done quickly by following up with another finger. A U2 can be done with a U (right index) followed by a U (right middle). An M2 can be done with M' (right ring) followed by an M' (right middle).